Toy vehicle with steerable wheels

ABSTRACT

A toy vehicle with a chassis (1), a pair of non-steerable wheels (2) and a pair of steerable wheels (3) mounted on the chassis, a reversible motor (4) mounted on the chassis and fitted with a first outlet shaft (5) associated with a transmission (6) for driving at least one of the non-steerable wheels in a forward direction regardless of the direction of rotation of the motor, and with a second outlet shaft (14) carrying at least one control tooth (15). The steerable wheels are mounted on supports (7) that are pivoted to the chassis about respective substantially vertical axes (8) and are interconnected by a tie-bar (11). A steering control stud (13) is carried by the tie-bar (11) and faces the second outlet shaft (14) and extends parallel thereto.

The present invention relates to a toy vehicle.

A toy vehicle is known, in particular from Document US-A-4 156 987, thatcomprises a chassis, a pair of non-steerable wheels, and a pair ofsteerable wheels mounted on the chassis, a reversible motor mounted onthe chassis and fitted with a first outlet shaft associated with atransmission for driving the non-steerable wheels in a forwardsdirection regardless of the direction of rotation of the motor, and witha second outlet shaft carrying a steering control member for thesteerable wheels, the steerable wheels being mounted on supports whichare pivoted to the chassis about respective substantially vertical axes,and which are interconnected by a tie-bar.

In the above-mentioned document, the control member comprises a frictionsleeve mounted on the second outlet shaft of the motor and co-operatingwith a plate pivoted on the vehicle chassis about an axis that issubstantially vertical and that is also pivoted to the tie-bar. Theplate extends beneath the friction sleeve to be driven thereby to theright or to the left depending on the direction of rotation of themotor. The capacity of a device of that type to steer the steerablewheels is linked to the amount of friction that the friction sleeveexerts on the steering control plate. This degree of friction is verydifficult to adjust and it has a direct effect on the general behaviorof the vehicle. If the degree of friction is high, then the steeringcontrol plate is driven appropriately each time the direction ofrotation of the motor reverses, however the motor is then braked eachtime it changes direction, thereby causing the vehicle to loose speed.In contrast, if the degree of friction is insufficient, then the vehicleis not braked, but the steerable wheels are not caused to steeradequately.

In existing devices, the friction sleeve has been replaced by a controlgear wheel that includes a series of teeth and the steering controlplate for the steerable wheels includes a stud that co-operates with thecontrol gear wheel. However, because of the oscillating movements of thecontrol plate, the control stud does not remain parallel to the secondoutlet shaft and it sometimes happens that the control stud escapes fromthe teeth of the controlling gear wheel when the motor reverses itsdirection of rotation, and as a result the steerable wheels do notalways change direction appropriately.

An object of the invention is to propose a vehicle that includes acontrol member that systematically ensures that the steerable wheelschange direction when the direction of rotation of the motor isreversed, while minimizing the extent to which the motor is slowed downat the moment it changes direction.

To achieve this object, the present invention provides a toy vehiclecomprising a chassis, a pair of non-steerable wheels and a pair ofsteerable wheels mounted on the chassis, a reversible motor mounted onthe chassis and fitted with a first outlet shaft associated with atransmission for driving at least one of the non-steerable wheels in aforwards direction regardless of the direction of rotation of the motor,and with a second outlet shaft carrying a steering control member forthe steerable wheels, the steerable wheels being mounted on supportswhich are pivoted to the chassis about respective substantially verticalaxes and which are interconnected by a tie-bar, wherein the controlmember includes at least one control tooth carried by the second outletshaft of the motor, and wherein a steering control stud is carried bythe tie-bar facing the second outlet shaft and extending parallelthereto.

Thus, when the direction of rotation of the motor is reversed, thecontrol tooth carried by the second outlet shaft of the motor comes intocontact over its entire length with the control stud carried by thetie-bar, and positive engagement is ensured for changing the directionof the steerable wheels.

In an advantageous version of the invention, the control stud istriangular in section having an edge directed towards the second outletshaft of the motor. Thus, while ensuring positive contact between thecontrol stud and the control tooth, friction between these two elementsis minimized and consequently slowdowns in the speed of rotation of themotor are also minimized.

In another advantageous aspect of the invention, the chassis includessteering abutments overlying the tie-bar, and the tie-bar includesprojecting shoulders for engaging the steering abutments. Thus, eachtime the direction of rotation of the motor is reversed, one ofshoulders on the tie-bar comes into contact with one of the steeringabutments overlying the tie-bar, thereby ensuring that the steerablewheels are positioned with great accuracy.

Other characteristics and advantages of the invention appear on readingthe following description of a particular, non-limiting embodiment ofthe invention given with reference to the accompanying drawing, inwhich:

FIG. 1 is a partially cutaway plan view of a toy vehicle of theinvention, with the bodywork of the vehicle being removed; and

FIG. 2 is a perspective view on a larger scale of the front portion ofthe toy vehicle of the invention.

With reference to the figures, the toy vehicle of the inventioncomprises a chassis 1, a pair of non-steerable wheels 2 mounted at therear of the chassis, and a pair of steerable wheels 3 mounted at thefront of the chassis. A reversible motor 4 is mounted on the mid-portionof the chassis and it is powered via contacts (not shown) projectingfrom the bottom face of the chassis to rub against power supply linescarried by a circuit that is also not shown. The reversible motor 4 hasa first outlet shaft 5 carrying a toothed wheel that is engaged inconventional manner with transmission means 6 associated with thenon-steerable wheels in order to drive them in a forwards directionregardless of the direction in which the motor is rotating.

The steerable wheels 3 are carried on L-shaped supports 7 that arehinged to the chassis about substantially vertical axes 8. One branch 9of each of the L-shaped supports 7 extends out from the chassis andcarries one of the steerable wheels 3, while the other branch 10 of theL-shaped support extends substantially in the longitudinal direction ofthe vehicle towards the rear thereof. The branches 10 of the steerablewheel supports are interconnected by a tie-bar 11 which is hinged to thebranches 7 of the steerable wheel supports about substantially verticalhinge axes 12. In its middle portion, the tie-bar 11 carries a controlstud 13 which extends rearwards over a second outlet shaft 14 of thereversible motor 4, and parallel thereto. The second outlet shaft 14carries two steering control teeth 15 which are symmetrically disposedabout the outlet shaft 14 such that the weight of the control teeth 15is balanced about the outlet shaft 14 and does not interfere with theoperation of the reversible motor 4 even when it is rotating at verygreat speed. The control stud 13 is naturally at a distance from thesecond outlet shaft 14 such that, when the motor 4 rotates, the teeth 15bear against the control stud 13 and urge it to the right or to the leftdepending on the direction in which the motor 4 is rotating.

In the preferred embodiment as illustrated, the control stud 13 istriangular in section and includes an edge 16 that faces towards thesecond outlet shaft 14. Thus, positive contact is ensured between one ofthe teeth 15 and the control stud 13 each time the direction of rotationof the motor 4 reverses, while nevertheless minimizing friction betweenthe teeth 15 and the control stud 13.

In addition, the chassis includes steering abutments 17 that overlie thetie-bar 11, and said bar includes projecting shoulders 18 for engagingthe steering abutments 17. Thus, each time the direction of rotation ofthe motor 4 reverses, the tie-bar 11 is pushed until one of itsshoulders 18 comes into contact with one of the steering abutments 17,such that the position of the tie-bar 11 and consequently the amount ofsteer applied to the steerable wheels 3 is determined with greataccuracy.

Naturally, the invention is not limited to the embodiment described, andvariant embodiments may be devised without going beyond the ambit of theinvention. In particular, although the control stud 13 in the embodimentdescribed is disposed above the second outlet shaft 14, it is possibleto have the control member 13 extending beneath the second outlet shaft14. Placing the control stud above the second outlet shaft isnevertheless preferred since that makes it easier for the control stud13 to escape should the steerable wheels 3 be jammed by a foreign body,thereby avoiding excessive wear of the control teeth 15 or of thecontrol stud 13.

Although the tie-bar 11 has been shown behind the pivot axes 8 of thesteerable wheel supports, the tie-bar could be disposed in front of saidpivot axes. It would also be possible to provide a second outlet shaftthat is fitted with more than two teeth, e.g. with a gear having sixteeth.

We claim:
 1. In a toy vehicle having a chassis (1), a pair ofnon-steerable wheels (2) and a pair of steerable wheels (3) mounted onthe chassis, a reversible motor (4) mounted on the chassis and fittedwith a first outlet shaft (5) associated with a transmission (6) fordriving at least one of the non-steerable wheels (2) in a forwarddirection regardless of the direction of rotation of the motor and witha second outlet shaft (14) carrying a steering control member for thesteerable wheels, the steerable wheels (3) being mounted on supports (7)which are pivoted to the chassis about respective substantially verticalaxes (8) and which are interconnected by a tie-bar (11), the improvementcomprising a control member having two teeth (15) carried by the secondoutlet shaft (14) of the motor (4) and disposed symmetrically about thesecond outlet shaft (14), and a single steering control stud (13) iscarried by the tie-bar (11) such that the stud faces the second outletshaft and extends parallel thereto.
 2. A toy vehicle according to claim1, wherein the control stud (13) is triangular in section, and has anedge (16) facing towards the second outlet shaft (14).
 3. A toy vehicleaccording to claim 1, wherein the chassis includes steering abutments(17) overlying the tie-bar (11) and the tie-bar includes projectingshoulders (18) for engaging the steering abutments (17).